1. Field of the Invention
The invention relates generally to devices and methods used to dispose tubewire into and remove it from radially surrounding tubing strings. In particular aspects, the invention relates to the insertion and removal of tubewire in situations wherein separate strings of coiled tubing are being connected.
2. Description of the Related Art
Coiled tubing has become a popular means for running a bottom hole assembly (“BHA”) or other tools into a subterranean wellbore. In most cases, it is desirable to be able to transmit electrical power down to the BHA or other tools as well as to permit control signals or sensed data to be transmitted between the surface and the downhole tools. Conventionally, this is done by disposing wireline into the coiled tubing. Wireline is a braided steel cable with layers of armor with conductors inside.
Use of wireline can be problematic. Wireline is prone to damage from acidic fluids in some instances. The slack in wireline must be adjusted over time, which requires time and money.
Tubewire is an alternative to wireline and has many advantages over wireline. Tubewire can be disposed inside coiled tubing to provide electrical power and a signal path from the surface to various downhole tools attached to the end of the coiled tubing. Tubewire is a tube that contains an insulated wire that is used to provide electrical power and/or data to the bottom hole assembly or to transmit data from the BHA to the surface. Tubewire is substantially inflexible relative to wireline. Tubewire is available commercially from manufacturers such as Draka Cableteq of North Dighton, Mass.
Tubewire can be disposed into coiled tubing at the surface. Systems and methods for injecting and retrieving tubewire into and out of coiled tubing are discussed in U.S. Pat. No. 7,845,419 by Naumann, which is incorporated herein by reference in its entirety. While the coiled tubing is spooled up on a reel at surface, the tubewire is placed into the coiled tubing by pumping fluid through the coiled tubing at high flow rates while an injector is used to feed the tubewire into the coiled tubing by applying a pushing force. According to the '419 patent, tubewire is pumped into the whip end (i.e., the end of the coiled tubing furthest away from the center of the reel) of the coiled tubing and toward the core end (i.e., the end of the coiled tubing nearest the center of the reel).
In many scenarios, such as off-shore situations, there are weight restrictions on equipment used to handle reels of coiled tubing, such as cranes. For this reason, a number of separate reels of coiled tubing are often used. These are moved one at a time by the crane or other handling equipment to a staging area for injection into the wellbore. The separate coiled tubing sections are joined together, then spooled up onto one reel and then injected into the wellbore from a single reel.